Apparatus for improving sheet delivery on automatic platen machines



Aug. 18, 1964 A. BUTTNER APPARATUS FOR IMPROVING SHEET DELIVERY Filed March 13, 1962 ON AUTOMATIC PLATEN MACHINES Fig.1

7 Sheets-Sheet 1 Aug. 18, 1964 BUTTNER 3,144,825

APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES Filed March 15, 1962 '7 Sheets-Sheet 2 Fig.2

I H H H 10 12 5 Filed March 15, 1962 A. BUTTNER APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES 7 Sheets-Sheet 3 Aug. 18, 1964 A. BUTTNER 3,144,825

APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES Filed March 15, 1962 7 Sheets-Sheet 4 1| 72 10 1 l I: 1! I. E l 22 1 M F l1"- 2a" 25 i I :3l I I "3 27 I I I H il l Aug. 18, 1964 A. BUTTNER 3,144,825

APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES Filed March 13, 1962 7 Sheets-Sheet 5 Aug. 18, 1964 A. BUTTN ER 3,144,825 APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES Filed March 15, 1962 7 Sheets-Sheet 6 Aug. 18, 1964 A. BUTTNER 3,144,825

APPAR S FOR IMPROVING SHEET IVERY AUTOMATIC PLATEN MACE-II Filed March 13, 1962 7 SheetsSheet 7 United States Patent Ofiice 3,144,825 Patented Aug. 18, 1964 3,144,825 APPARATUS FOR IMPROVING SHEET DELIVERY ON AUTOMATIC PLATEN MACHINES Artur Biittner, Heidelberg, Germany, assignor to Schnellpressenfabrilr Airtiengesellschaft Heidelberg, Heidelberg, Germany, a corporation of Germany Filed Mar. 13, 1962, Ser. No. 179,363 Claims priority, application, Germany, Apr. 8, 1961, Sch 29,512 16 Claims. (Cl. 101-297) The present invention relates to automatic platen machines, more particularly to the type wherein the feed and delivery of sheets is effected by periodically rotated grippers which are mounted for reciprocable travel with the platen and rotatably driven substantially in the plane of the platen.

In machines of this kind the delivery stack is arranged at the side of the platen in such a manner that, when the platen is in the open position, the sheets, for example printed sheets, can be delivered from the gripper directly onto the delivery stack. On delivery from the platen to the delivery stack, the sheet, which is gripped at a leading edge by the gripper and carried clear of the platen, describes or moves along a kind of helical path. The helical path results from the fact that during the opening movement of the platen the sheet is simultaneously being moved along an arcuate path over the delivery stack. Due to this complex movement, difficulties occur in the delivery of light stock or flimsy sheets of paper which are difficult to control. Because of the opening movement of the platen, the sheets being delivered from the platen to the delivery stack tend to rise and do not tend to settle onto the delivery stack once released by the grippers and, therefore, neat stacking with the sheets in registry becomes very dihicult.

In order to overcome this difficulty various blowing devices are used to assist in delivery of the sheets. It has been proposed to take the individual sheets from the periodically actuated grippers and to draw them forwardly across the delivery stack. In order to hold the sheets down a jet of air is also applied. An improvement in the delivery of the individual sheets is achieved with these devices, but it is still not possible to use high machine operating speeds with papers or stock which are diiiicult to print. Usually, however, the stocks which are difficult to print on are the ones used for cheap, simple printed material which has to be printed at high machine speeds in order to do the job economically.

It is a principal object of the present invention to provide apparatus overcoming the above-mentioned difficulties and improving sheet delivery.

According to the present invention a platen printing or punching press is provided with grippers which are rotated periodically substantially in the plane of the platen in timed relationship with the reciprocable movement of the platen to convey individual sheets to be processed, from a feed stack or pile to the platen and afterwards from the platen to a delivery stack. Means defining a substantially air-impervious support surface additional to the working surface of the platen and substantially in the plane of the platen working surface is provided to support the sheet during movement from the platen to the delivery stack. The additional supporting surface reciprocates with the platen.

A principal feature of the apparatus according to the present invention, for improving sheet delivery resides in the fact that the additional surface provided adjacent to the platen on the delivery side as a support for the sheets corresponds in area to approximately the maximum size of sheet or stock used and at least part thereof is reciprocated with the platen. This surface is a device forming a part of the platen itself or is attached to the platen in the form of a plate or a roll of flexible material which can be rolled and unrolled. When the surface is attached to the platen, the delivery stack is covered by the surface when the platen is in the open position. In this case the sheet stock is removed either at the front or at the side of the supporting surface or a controlled movement of the supporting surface itself must be effected. If a roll device is used it must be rolled up to the delivery stack for a short time to decrease the area of the support surface to permit access to delivery of the processed sheet onto the stack clear of the support surface.

In other embodiments of the invention the printed sheet is retained on the supporting surface and additional suction members or grippers grip the sheet just before the opening of the periodically rotated grippers and by additional feed means convey it to the delivery stack which can be arranged in front of or at a side of the supporting surface.

The supporting surface for the sheet, provided adjacent to the platen, is primarily for improving delivery of the sheets when the sheet is swung from the platen into a position for delivery to the delivery stack. During this movement the device, comprising the support surface defined by an air-impervious plate or air-impervious roll according to the invention screens, the back of the sheet from any eddy currents of air due to the opening movement of the platen which hitherto caused the sheet to rise. The screening takes place while the printed side of the sheet and the sheet itself are exposed to the partial vacuum developed on the back of the swinging surface and platen, whereby smooth application of the printed sheet is considerably assisted. As a result of this supporting surface thin stock can be printed at high machine operating speeds, and economy in completing various printing operations is greatly increased thereby.

The invention will be described further, by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a fragmentary plan view of a platen printing press with its platen in open condition and provided with apparatus according to the invention illustrated as a support surface mounted next to the press platen;

FIG. 2 is a plan view similiar to the view in FIG. 1 and illustrates diagrammatically an embodiment of the invention in which a part of the supporting surface is retractable from its extended position to uncover a delivery stack for delivery of sheets thereon;

FIG. 3 is a plan view similar to the view in FIG. 2 illustrating an embodiment of the invention as a roll or blind-like device instead of a supporting surface capable of displacement, as illustrated in FIG. 2;

FIG. 4 is a fragmentary plan view similar to the view in FIG. 3 illustrating mechanism for the displacement movement of a part of the supporting surface according to the invention;

FIG. 5 is a fragmentary side elevation view of a platen printing press illustrating the platen in the closed or printing position and a supporting surface for the printed sheets displaceable by another embodiment of mechanism according to the invention;

FIG. 6 is a fragmentary side elevation view of the mafhine in FIG. 5 with the platen in an opened condition; an

FIG. 7 is a fragmentary side elevation of a platen press provided with a hinged upper part of a supporting surface and additional swinging grippers for removing the printed sheets from the supporting. surface to the delivery pile or stack according to the invention.

While the invention will be described and illustrated as applied to a platen printing press it will be understood that the invention is equally applicable toother platen 6 machines where sheets are processed for example, punched and/ or perforated. Moreover, in order to simplify the disclosure like reference numerals are employed throughout to refer to alike or similar parts in the various embodiments of the invention.

In the machine illustrated in FIG. 1 a platen 1 is pivotally mounted by a shaft 2 on a base frame 3 shown fragmentarily. The shaft 2 is press fitted in the platen and its opposite ends are journalled in the base frame. A gripper head 4 which houses driving mechanism, not shown, for periodic rotation of a pair of grippers, hereafter described, through 90 respectively, is rigidly attached to the platen 1 for reciprocable travel therewith. A gripper carrier 6 having two arms which support two parallel grippers 7 and 8, is firmly pressed on a shaft of the gripper head or drive. The grippers alternately take sheets individually from a feed stack and deliver them onto the platen 1. The sheets are raised individually by known means such as suction members, not shown, from the stack 9 and the forward edge thereof is transferred alternately to the grippers 7 and 8 for delivery to the platen 1 in its open condition. After the sheet is transferred by the suction members while the platen is in an open condition and during the closing movement of the platen, the sheet engaged by a gripper, for example gripper 7, is drawn in an arc to the surface of the platen and held thereon while printed.

The pair of grippers are disposed in a perpendicular position in the closed or printing position of the platen. After the printing operation the gripper 7 moves in an arc over a delivery stack 10 to the position occupied by the other gripper 8. The stack 10 is arranged in known manner adjacent to the platen so that, after the opening of the gripper 7 in its release position the sheets are delivered onto a delivery stack and directly between two side supports or guides 11 and paper abutments 12. The gripper 8 meanwhile has moved to a position where it is ready to receive the next sheet from the feed stack 9.

In FIG. 1 intermediate positions 7', 8 of the pair of grippers 7, 8 are shown in broken lines in the position in which they have not quite reached their intermittent stop positions and are illustrated as delivering a thin stock sheet 13. Each of the grippers 7 and 8 turns through a 90' are twice while idling, i.e. without a sheet, and through 90 in the time which follows the delivery of the sheet during the closing movement of the platen 1 and through another 90 during the following opening movement of the platen. The grippers describe their arcuate paths substantially in the plane of the platen 1. During this idling rotation of twice 90 of one of the grippers the other gripper has drawn an unprinted sheet from the feeding stack 9 and delivered it onto the platen 1 and, after printing the sheet, conveyed it over the delivery stack 10. While the gripper with the sheet is being rotated in an arc through 90 to deliver the printed sheet the platen is simultaneously opening out and away from a vertical, or approximately vertical upstanding printing or closed position into the opened position in which the platen is inclined relative to the vertical position. During this movement, in known printing presses, the sheet is removed from the platen and loses its support. Thus the sheet tends to rise since it is raised by the air below it as a consequence of the opening movement of the platen. This behavior on the part of the sheet was hitherto countered, as is well known, by a blast of air which sweeps over the upper surface of the sheet. As has already been mentioned the present invention relates to platen printing presses which work on this principle, since it is such cases that the undesirable effects in the delivery of the sheets occur which it is the object of the invention to remove.

In order to overcome the undesired effects heretofore described in the type of platen press described the press platen 1 is provided with means defining a surface 14 which acts as a support for the sheet as it swings out from the platen. It may be seen from FIG. 1 that a sheet 13 gripped by the gripper 8 being stacked in the delivery stack rests completely on the supporting surface 14. This surface substantially forms a part of the platen 1. It is preferable to attach this supporting surface on the platen 1 in the form of a light plate 14 which forms the supporting surface as shown in FIG. 1. This supporting surface is shaped such that, when the largest sheet which can be printed swings out, in an arcuate path, the sheet is always supported on this surface during its travel. That is to say, the major face or dimension of the sheet rests on the support. The supporting surface itself is spaced closely below the platen surface 1, just low enough that the grippers 7 and 8 can move over it with a small clearance. Thus the support surface is substantially in the plane of the platen or working surface thereof.

As can be seen in FIG. 1 the delivery stack 10 is covered by the arrangement of this supporting surface 14. The sheet cannot fall directly onto the delivery stack 10 as is the case in known platen printing presses heretofore described and in which an arrangement according to the invention is not employed. It can be seen that the plate 14 acts as a screen against eddy currents of air to which the printed sheet would normally be subjected during the opening movement of the platen. Other gripper means not shown, hold the sheet upon release by the grippers as the platen returns to a closed position so that the sheet is delivered accurately onto the delivery pile without trouble. The other grippers comprise a gripper arrangement, for example of the type of suction tube 18 illustrated in FIG. 4, which grips the leading marginal portion before the rotatable grippers release the individual sheets. These other grippers release the sheets in a delivery position by mechanism, not shown.

In FIG. 2 the numerals 1 to 13 designate parts similar to those described in FIG. 1 in order to simplify the drawings. Moreover, hereinafter equivalent parts are designated with reference numerals in which two digits are the same and third digit corresponds to the figure in which the part is to be found in order to correlate the various embodiments of the invention. The supporting surface for the sheet 13 is a two-part surface. A part 142 is rigidly secured to the platen 1 and its size is such that it does not cover the delivery stack 10 when the platen 1 is in the open position. A displaceable part or plate 15 forms an extension of the plate 142 and assumes the position 15 when the platen reaches its open position. The portion 15 of the screen in this embodiment is free to move in a longitudinal direction on tracks or guides, not shown, under control of mechanical mechanism driven from the press and timed to move the portion 15 once the platen has opened and while the part 15 overlies the delivery pile. The movement of the part 15 is indicated by the arrow and is carried out after the sheet 13 has been moved over the delivery stack 10. The displaceable part of the supporting surface is moved in the direction of the arrow by the amount x in order to uncover the delivery stack 10 to receive the sheeet 13, which is delivered onto the delivery pile accurately positioned once the part 15 is retracted. The displaceable part is restored to its upper position 15 forming an extension of the surface portion 142 during the closing movement of the platen so the press can be operated at top speed. The displacement movement of the surface 15 may also be effected in a lateral direction, which is not preferred because more space is required.

In the embodiment of the invention illustrated in FIG. 3 the numerals 1 to 13 designate parts similar to those illustrated and described in FIG. 2. The movable supporting surface 15 is replaced by a roll 16 automatically winding and unwinding at the proper time. This roll member 16 is operated from the machine. A rocker arm 17 operably connected to movable parts, not shown, of the platen printing press, for actuation therefrom carries a spindle of the roll arrangement 16 mounted thereon. The arm 17 allows the roll to wind up during the time in which the gripper with the printed sheet 13 moves across the delivery stack and allows disposition of the sheet 13 on the delivery stack.

The roll 16 is made of a material capable of being rolled up, for example cloth. One end of the cloth, which is wound and unwound, is secured to a front edge of a surface 143 firmly secured to the platen 1. The other or free end of this cloth winding arrangement winds and unwinds in known manner automatically on a spindle which is secured to the rocker arm 17. The arm is reciprocated synchronously with. the movement of the platen in such manner that the roll device 16 is unwound as soon as the gripper with the engaged sheet swings out and the roll spindle assumes an upper position 16 illustrated with the rocker arm in its upper position 17 with the roll cloth fully extended. This upper end position is illustrated with the platen completely open. It will be understood that the unwinding operation takes place sufliciently rapidly so that the roll acts as a screen and support as heretofore described with respect to the other embodiments of the invention. The rocker arm is then rocked to permit the roll to wind up automatically under control of winding means, for example a spring, not shown. The winding up movement allows the printed sheet 13 to fall onto the delivery stack unimpeded. In this embodiment the lower supporting surface 143 with the platen 1 executes a swinging movement, while the winding and unwinding of the upper part of the supporting surface is effected by separate control means, not shown, driven from the press to control in the roll device 16.

In FIG. 4 an embodiment is shown in which the reciprocating movement of the upper part of the supporting surface is effected by means controlled by compressed air or hydraulic fluid under pressure. The numerals for parts 1 to 13 are the same as those already described with respect to the other embodiments, for example FIG. 2. In FIG. 4 a suction tube 18 connected to the suction pump of the press, is mounted on the side support 11 by means of a bracket 19 comparable to the embodiment disclosed in FIG. 5 and hereafter described. The suction tube 18 extends across the width dimension of the sheet and grips the printed sheet 13 along a leading marginal portion just before the grippers 7 or 8 open, in the open position of the platen 1, retains the sheet 13 until a displaceable supporting surface 154, comparable to the surface 15 of FIG. 2, below it has moved downwardly and uncovered the delivery stack 10 to deposit the sheet 13. The application of a suction vacuum through axially disposed apertures, not shown, on the tube 18 is timed by mechanism, not shown, synchronously with the stroke of the platen and other operations. The vacuum is broken by this mechanism after the upper support surface retracts and slides out from under the sheet and the sheet falls or slides onto the delivery stack as the platen makes its closing movement for the next printing operation.

In this construction the displaceable part 144 is a thin plate forming an extension or continuation of a supporting surface 144, comparable to surface 14 in FIG. 2, rigidly connected to the platen. The displaceable plate or surface 154 is connected by a bracket 20 to a reciprocably driven piston rod 21. The bracket 20 is attached to plate 154 adjacent its right hand corner beneath the plate. The rod and connecting bracket tend to support the right hand portion of the plate. The outer or left hand marginal edge portion of the displaceable supporting surface 154 is supported in a guide groove 22 mounted on the plate 144 so that the movable plate 154 is capable of reciprocable travel longitudinally. It moves beneath the plate or surface 144 with a very small space or clearance in the order of one or two millimeters. The piston rod 21 is connected to a piston 23 reciprocable in a cylinder 24. The cylinder 24 is rigidly attached to the platen shaft 2 so that it positively participates in the opening and closing movement of the platen and moves synchronously therewith. Compressed air or hydraulic fluid actuates the piston in the cylinder 24 under control of the plug of a control valve 25 which is turned through at the right moment by means, not shown, actuated by the machine.

In the open position of the platen, as shown in FIG. 4, the compressed air or hydraulic fluid under pressure flows through a line 26 into the upper part of the cylinder 24 and depresses the piston 23 and actuates jointly therewith the piston rod 21 and the bracket 20, so that the displaceable supporting surface 154 is retracted sufficiently to clear the sheet 13. The upward movement of the piston 23 during the opening movement of the platen 1 takes place after the plug of the valve 25 is reversed and compressed air or pressure fluid then urges the piston 23 upwardly under control of pressure fluid applied through a pipe 27 which leads to the lower part of the cylinder 24 thereby restoring the plate 154 to its upper position. A supply line 28 connected to an air pump or oil pump, not shown, provides the actuating fluid under pressure. It being understood that suitable exhaust connections are provided, not shown, so that the reciprocating system forms a closed system. The cylin der 24 can also be secured to the base frame 3 and in that casetransmit the movement of its piston to the displaceable supporting surface 154 by way of a draw bar, not shown.

Another embodiment of the invention is illustrated in FIG. 5 in which the platen 1 of a printing press is shown in the closed position. This embodiment relates to retraction and restoration of a movable supporting surface produced by mechanical means. The reference n11- merals 1 to 15 and 18 and 19 designate similar parts as in the above-described embodiments. In this embodiment the displaceable portion 155 of the supporting surface formed by 145, 155 is capable of moving to and fro in the form of a rolling truck with rollers which run on guide rails 33. The lower end portion of the displaceable supporting surface 155 is provided with an arm 30 pivotally connected by a pin 31 to a draw bar 32. The other end of the draw bar is pivotally connected by a pin 34 fixed to an endless chain 35 of a chain drive having driven chain wheels or sprockets 36 and 37 which are journalled to rotate in known manner on the base frame 3 on pivot pins 38, 39. The chain drive is driven from the machine, by means not shown, in such manner that one complete revolution of the chain 35 occurs per print or impression.

The press is provided with a bracket 40 which supports the feeding and delivery stacks with appropriate conveying devices. The bracket 40 is secured to the base frame 3. A gear rack 41 carries a plate 42 which receives the delivery stack 10. During the operation of the machine the gear rack 41 with the plate 42 moves slowly downwardly according to the increase in the stack 10 in known manner. FIG. 5 illustrates how a printed sheet 13, after release from the grippers 7 or 8, is retained by the suction tube 18 secured by the bracket 19 to the side support 11. Since the platen 1 has returned to its closed position and the displaceable supporting surface 155 is in its lower or retracted position, the sheet 13 is released somewhat earlier for depositing on the delivery stack 10 than the operating position shown in FIG. 5.

FIG. 6 illustrates how the device, described with reference to FIG. 5 with the platen 1 in an open position spaced apart from a form or plate 43 which is received in known manner by the base frame 3. Inking rolls 44 for inking the printing form 43 are illustrated in the lowest position. With punching platens which operate without inking mechanism these printing devices are unnecessary. The moment the grippers 8 open, the previously printed sheet 13 is sucked by the suction tube 18 by applying suction to its back surface. It is to be understood that instead of this suction device 18 grippers, not shown, may be used.

The displaceable surface which, in this case, comprises a thin and light metal plate or surface 155 is actuated by the previously described chain drive 3539 and draw bar 32, into its upper or extended position. It, therefore, practically completely covers the delivery stack 10. This upward movement of the supporting surface 155 is effected during the opening movement of the platen 1 and while the gripper with the printed sheet 13 is swinging out from the platen 1. The upward movement of the plate 155 is effected sufficiently rapidly so that the plate, which is air-impervious, effectively screens the sheet 13 during its arcuate travel and simultaneous descending movement of the platen and grippers. After the open position of the platen 1 is reached and the sheet 13 is to be delivered to the delivery stack the descending movement of the supporting surface 15 can be effected at the fastest possible rate. The chain drive 354:9 requires much less time for the downward movement or retraction of the supporting surface 155 than for the upward movement as can be seen from the direction of rotation and the arrangement of the chain and associated members of the chain drive.

Another embodiment of the invention is illustrated in FIG. 7. This embodiment differs from those already described in that a supporting surface 157 comparable to the supporting surface 15 is not retractable but is pivotally mounted to the platen 1 so as to be capable of swinging. The reference numerals 1 to 13 designate the parts similar to those previously described. However, this construction is different from those already described; in that in this construction a supporting surface 147, comparable to the surface 14, is fixed to the platen and the upper supporting surface 157 is hinged on a pin which is rigidly connected to the platen 1. The hinged supporting surface 157 is operable to a raised position designated I at the moment the sheet is taken over by the suction tube 18 which, in this case, is connected to the surface 157. The application of a suction to the suction device 18 and breaking thereof is carried out by mechanism, including a vacuum pump on the press, not shown, in timed relationship with the operations of the press hereinafter described. As soon as the gripper 8 opens and a suction is applied to the rear surface of the sheet 13 the surface 157 with the attached sheet is moved into an intermediate lower position II. A gripper or suction system 51 provided on a rockable lever 52 grips the sheet by the front or leading edge at position II and upon an outward or counterclockwise movement of the lever 52, the printed sheet is drawn downwardly from the surface 157. During this period the platen closes and the surface 157 is lowered to a lowermost position designated Ill. The suction system 51 holds the individual sheets as they are swung outwardly to a position illustrated by broken lines until the trailing end of each sheet is drawn off from the component surface 157 and has dropped onto the stack 10 in registry therewith disposed between the side walls 11 and the lower abutment 12.

The reciprocating movement of the gripper or suction system 51 is effected, by the rockable lever 52 which has its lower end pivoted by pins 53 in a bearing 54. The bearing 54 is secured to a bracket 40. A draw bar 56 pivotally connected by a pin to the lever 52 has the other end pivotally connected by a pin 57 to a crank 58. The crank 58 is rigidly connected to the platen shaft 2 and participates in the swinging movement of the platen. This movement is utilized to derive the swinging movement of the lever 52. The arm 58 is so positioned that as the platen starts its closing movement it moves to higher position illustrated by broken lines to rock the lever of its outermost position.

This embodiment illustrates an example of the manner in which a printed sheet is drawn off the supporting surface 147, 157. It is, of course, possible to arrange the pivot point 50 for the surface 157 much lower so that the entire length of the printed sheet rests on the hinged supporting surface 157. The delivery stack arrangement and the path of swing of the gripper or suction system 51 change accordingly. The mechanism for pivoting the upper support surface comprises mechanism, not shown, comparable to those heretofore described for retracting and restoring the support surface. In this embodiment the mechanism either mechanical or hydraulic is connected to the hinged part of the support surface and actuates this part to its three positions in timed sequence with the other operations.

In printing sheets of small format or thick papers or cardboard which do not tend to rise, it is possible to eliminate the movement of the retractable surface, designated by at least two reference numerals 15 in the various embodiments by suitable means. For example, the mechanisms actuating the surface 15 can be immobilized so that it is fixed in its lowest or retracted position. In this manner platen printing presses provided with apparatus according to the invention can handle all types and sizes of stock at suitable delivery rates and the presses operated with utmost economy.

What I claim and desire to secure by Letters Patent is:

1. In a machine having a platen cyclically reciprocable in opposite directions between a terminal first position and a terminal second position spaced apart from said first position and having gripping means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during movement of said platen toward said second position to deliver sheets individually from the platen to a delivery stack upon completion of the opening movement of said platen, the improvement which comprises, means substantially air impervious to permit accurate and easy stacking of said sheets on said delivery stack comprising, means defining a support surface substantially in said plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during their travel along said arcuate path and during substantially the entire opening movement of said platen and the last mentioned means comprising means selectively movable relative to said platen in timed relationship with the movement of said platen for reducing the area of said support surface when the sheets are to be delivered to said delivery stack substantially upon completion of the movement of a platen.

2. In a machine having a platen cyclically reciprocable in opposite directions between a terminal first position and a terminal second position spaced apart from said first position and having gripping means comprising means for gripping sheets individually on said platen mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during movement of said platen toward said second position and operable to deliver said sheets individually from the platen to a delivery stack upon completion of the opening movement of said platen, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack comprising, means defining a support surface substantially in said plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during their travel along said arcuate path and during substantially the entire opening movement of said platen, and the last mentioned means comprising means selectively movable relative to said platen in timed relationship with the movement of said platen for reducing the area of said support surface when the sheets are to be delivered to said delivery stack substantially upon completion of the movement of a platen and means cooperative with the first mentioned means to deliver the sheets from said support surface to said delivery stack subsequent to completion of movement of said platen to said second position.

3. In a machine having a platen cyclically reciprocable in opposite directions between a terminal closed position and terminal opening position spaced apart from said closed position and having gripping means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the-platen during movement of said platen toward said open position to deliver sheets individually from the platen to a delivery stack upon completion of the opening movement of said platen and to deliver sheets individually from a feed stack to said platen while said platen is open, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack comprising means to cause the individual sheets to be delivered to said delivery pile substantially free of the effect of air currents during the reciprocable travel of said platen to said open position toward said delivery stack, the last-mentioned means comprising means defining an air-impervious support surface adjacent said platen to support the individual sheets along their major face dimension when taken from said platen and during substantially the entire opening movement of said platen, and the last mentioned means comprising means selectively movable relative to said platen in timed relationship with the movement of said platen for reducing the area of said support surface when the sheets are to be delivered to said delivery stack substantially upon completion of the movement of said platen.

4. In a machine according to claim 3, in which said platen has a face and said means defining said support surface is attached to said platen and forms substantially a continuation of the face of said platen.

5. In a machine according to claim 3, in which said support surface is disposed substantially in the plane of the platen to support said sheets during travel thereof along said arcuate path.

6. In a machine having a platen cyclically reciprocable in opposite directions between a terminal upstanding position and a terminal open position spaced apart from said closed position in which the platen is inclined with respect to said upstanding position, and having gripper means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during the opening movement of said platen to deliver sheets individually from the platen to a delivery stack adjacent said terminal open position, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack with said sheets in registry with one another comprising means to cause the individual sheets to be delivered to said delivery stack substantially free of the effect of air currents during the reciprocable travel of said platen to said open position toward said delivery stack, the lastmentioned means comprises substantially air-impervious means defining a support surface substantially in the plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during the entire opening movement of said platen, said air-impervious means comprising two plates jointly forming said support surface, means mounting one of said plates for travel relative to the other plate to a first operative position in which said plates jointly form said support surface and to a retracted operative position partially underlying said other plate to reduce the area of said support surface thereby to permit a sheet held by said grippers to clear said support surface for delivery onto said delivery stack when said one plate assumes said retracted position, and means for actuating said one plate between said two operative positions in timed relationship with the movement of said platen and said grippers.

7. In a machine according to claim 6, in which said means for actuating said one plate comprises a cylinder,

a piston reciprocable in said cylinder, means connecting said piston to said one plate, and means for effectively controlling reciprocation of said piston in timed relationship with said platen and said grippers.

8. In a machine according to claim 7, comprising means mounting said cylinder in said machine for traveling movement with said platen, and in which said means connecting said piston and said one plate comprises a piston rod for actuating said one plate substantially parallel to said plane of said platen.

9. In a machine according to claim 6, in which said means for actuating said one plate comprises, means defining a track for said one plate to travel parallel to said plane of said platen, a driven drive, and means connected to said drive for reciprocably driving said one plate along said track.

10. In a machine according to claim 9, in which said drive comprises a driven endless chain, and said means connected to said drive comprises a bar pivotally connected to said chain and pivotally connected to said one plate.

11. In a machine having a platen cyclically reciprocable in opposite directions between a terminal upstanding, closed position and a terminal open position spaced apart from said closed position in which the platen is inclined with respect to said upstanding, closed position, and having gripper means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during the opening movement of said platen to deliver sheets individually from the platen to a delivery stack adjacent said terminal open position, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack with said sheets in registry with one another comprising means to cause the individual sheets to be delivered to said delivery stack substantially free of the effect of air currents during the reciprocable travel of said platen to said open position and toward said delivery stack, the last-mentioned means comprising substantially air-impervious means defining a support surface substantially in the plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during the entire opening movement of said platen, said air-impervious means comprising two plates jointly forming said support surface, means mounting one of said plates for travel relative to the other plate to a first operative position in which said plates jointly form said support surface and to a retracted operative position partially underlying said other plate to reduce the area of said support surface thereby to permit a sheet held by said grippers to clear said support surface for downward movement onto said delivery stack when said one plate assumes said retracted position, means for actuating said plate between said two operative positions in timed relationship with the movement of said platen and said grippers, and means to deliver the sheets from said support surface to said delivery stack subsequent to completion of movement of said platen to said open position.

12. In a machine having a platen cyclically reciprocable in opposite directions between a terminal closed position and a terminal open position spaced apart from said closed position, and having gripper means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during the opening movement of said platen to deliver sheets individually from the platen to a delivery stack adjacent said terminal open position, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack With said sheets in registry with one another comprising means to cause the individual sheets to be delivered to said delivery stack substantially free of the effect of air currents during the reciprocable travel of said platen to 11 said open position toward said delivery stack, the lastmentioned means comprising substantially air-impervious means defining a support surface substantially in the plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during the entire opening movement of said platen, said air-impervious means comprising a roll of flexible material for intermittently forming said support surface, means for extending said roll to a first operative position in which said roll forms said support surface and to a retracted operative position to reduce the area of said support surface thereby to permit a sheet held by said grippers to clear said support surface for downward movement onto said delivery stack when said roll assumes said retracted position, and means for actuating said roll between said two operative positions in timed relationship With the movement of said platen and said grippers.

13. In a machine having a platen cyclically reciprocable in opposite directions between a terminal upstanding closed position and a terminal open position spaced apart from said closed position in which the platen is inclined with respect to said upstanding position, and having gripper means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during the opening movement of said platen to deliver sheets individually from the platen to a delivery stack adjacent said terminal open position, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack with said sheets in registry with one another comprising means to cause the individual sheets to be delivered to said delivery stack substantially free of the efiect of air currents during the reciprocable travel of said platen to said open position toward said delivery stack, the last-mentioned means comprising substantially air-impervious means defining a support surface substantially in the plane of said platen to support the individual sheets along their major face dimension when taken from said platen and during the entire opening movement of said platen, said air-impervious means comprising two plates jointly forming said support surface, hinge means mounting one of said plates for pivotal movement relative to the other plate to a first operative position in which said plates jointly form said support surface and to a lowered operative position partially inclined relative to said other plate to permit a sheet held by said grippers to clear said support surface for delivery onto said delivery stack when said plate assumes said lowered position, and means to deliver the sheets from said support surface to said delivery stack subsequent to completion of movement of said platen to said open position while said one plate is in a lowered position.

14. In a machine according to claim 13, in which means to deliver the sheets from said support surface to said delivery stack comprises other grippers, means for actuating said other grippers into position to grip said sheets individually while said plates form said support surface and for actuating said other grippers to a delivery position for delivering said sheets onto said delivery stack in uniform registry when said one plate is inclined relative to said other plate.

15. In a machine according to claim 14, in which said means for actuating said other gripper system comprises support means operable to a position holding said gripper system adjacent said lowered position to grip an edge of said individual sheets, and means to rock said support means to another position for releasing said sheet directly onto said delivery stack, and means operably connecting said support means to said platen for reciprocable travel therewith to time the movement of said other gripper means with the movement of said platen and plates forming said support surface.

16. In a machine having a platen cyclically reciprocable in opposite directions between a terminal closed position and terminal open position spaced apart from said closed position and having gripping means mounted for synchronous reciprocable travel with said platen and simultaneously traveling in an arcuate path in the plane of the platen during movement of said platen toward said open position to deliver sheets individually from the platen to a delivery stack upon completion of the opening movement of said platen and to deliver sheets individually from a feed stack to said platen while said platen is open, the improvement which comprises, means to permit accurate and easy stacking of said sheets on said delivery stack comprising means to cause the individual sheets to be delivered to said delivery pile substantially free of the effect of air currents during the reciprocable travel of said platen to said open position toward said delivery stack, the last-mentioned means comprising means defining an air impervious support surface adjacent said platen to support the individual sheets along their major face dimension when taken from said platen and during substantially the entire opening movement of said platen, said last-mentioned means comprising means disposed to overlie said delivery stack upon substantial completion of the movement of said platen to said open position and selectively movable relative to said platen in timed relationship with the movement of said platen for reducing the area of said support surface when the sheets are to be delivered to said delivery stack substantially upon completion of the movement of said platen.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A MACHINE HAVING A PLATEN CYCLICALLY RECIPROCABLE IN OPPOSITE DIRECTIONS BETWEEN A TERMINAL FIRST POSITION AND A TERMINAL SECOND POSITION SPACED APART FROM SAID FIRST POSITION AND HAVING GRIPPING MEANS MOUNTED FOR SYNCHRONOUS RECIPROCABLE TRAVEL WITH SAID PLATEN AND SIMULTANEOUSLY TRAVELING IN AN ARCUATE PATH IN THE PLANE OF THE PLATEN DURING MOVEMENT OF SAID PLATEN TOWARD SAID SECOND POSITION TO DELIVER SHEETS INDIVIDUALLY FROM THE PLATEN TO A DELIVERY STACK UPON COMPLETION OF THE OPENING MOVEMENT OF SAID PLATEN, THE IMPROVEMENT WHICH COMPRISES, MEANS SUBSTANTIALLY AIR IMPERVIOUS TO PERMIT ACCURATE AND EASY STACKING OF SAID SHEETS ON SAID DELIVERY STACK COMPRISING, MEANS DEFINING A SUPPORT SURFACE SUBSTANTIALLY IN SAID PLANE OF SAID PLATEN TO SUPPORT THE INDIVIDUAL SHEETS ALONG THEIR MAJOR FACE DIMENSION WHEN TAKEN FROM SAID PLATEN AND DURING THEIR TRAVEL ALONG SAID ARCUATE PATH AND DURING SUBSTANTIALLY THE ENTIRE OPENING MOVEMENT OF SAID PLATEN AND THE LAST MENTIONED MEANS COMPRISING MEANS SELECTIVELY MOVABLE RELATIVE TO SAID PLATEN IN TIMED RELATIONSHIP WITH THE MOVEMENT OF SAID PLATEN FOR REDUCING THE AREA OF SAID SUPPORT SURFACE WHEN THE SHEETS ARE TO BE DELIVERED TO SAID DELIVERY STACK SUBSTANTIALLY UPON COMPLETION OF THE MOVEMENT OF A PLATEN. 